But polar cod, capelin, sand eel (Ammodytes spp.), and squid (Illex illecebrosus) are probably the most important pelagic/semi-pelagic macrofauna acting as forage for fish such as Greenland halibut and cod, marine mammals, and seabirds.

Greenberg says that the concentrations of oxygen would be great enough to support not only microorganisms, but also “macrofauna”, that is, more complex animal-like organisms which have greater oxygen demands.